It is often desirable to measure the real time change in thickness of objects which are subjected to processes or forces which may or are intended to change those thicknesses. There are a number of situations where it would be a great advantage to be able to measure the thickness or changes in thickness as a function of time. This is particularly true in tubes such as gun barrels, hollow cylinders, pipes, or, in fact, any component direction of a material bounded by surfaces which can reflect sound waves or to which sound waves can be coupled.
It has not been possible at this time to monitor the thickness of materials over a period of time in which the information sought, such as the thickness of a tube, for example, is compared with desired results or limitations on the process in order to control the operation of the process. Limited efforts have not met with success in this area.
Prior art attempts to measure thicknesses of gun barrels and the like are described in U.S. Pat. No. 5,182,139, in the name of J. Frankel and M. Doxbeck issued on Jan. 26, 1993, based on Ser. No. 760,636 filed Sep. 16, 1991. However, it is not possible in that system to enable the user to continuously or intermittently or by remote command in any time interval measure the thickness changes under conditions in which the temperature of the specimen changes.
Accordingly it is an object of this invention to provide a method and system for measuring thicknesses of samples which are subject to change of temperature during the measurement process.
Another object is to provide a system that can be used with a computer to provide instantaneous comparison with specified parameters in order to control an ongoing process such as, for example, plating of a gun barrel.
Still another object of the invention is to provide a method in which the rate of change of thickness with respect to time can be calculated and compared at several locations on the sample.
Other Objects will appear hereinafter.